The invention relates to a plant for refining molten pig iron with a converter, that is surrounded by a carrying ring and is tiltable about a horizontal axis by means of oppositely arranged carrying trunnions, and with a water-cooled blowing lance, that is liftably and lowerably arranged at a stationary vertical lance guide for supplying oxygen-containing refining gas, preferably technically pure oxygen, and, if desired, finely grained fluxing agents, e.g. lime.
Plants of this kind, in which oxygen is blown from above onto the metal bath, require blowing lances of substantial structural length; in large converter plants this length is more than 20 m. Accordingly, the stationary lance guide arranged at a distance above the converter or above the chimney hood so as to close it during blowing must be constructed very heavily and the converter hall must be very high in this area, which results in substantial investment costs for constructing such steel making plants. The great building height of these so-called LD-steel-making plants is also an obstacle to replacing the open-hearth furnaces still in use with LD converters (top-blowing converters), which are highly productive; i.e. it is difficult to install converter plants having liftable and lowerable oxygen blowing lances into already existing open-hearth furnace steel making plants.